The semiconductor integrated circuit (IC) industry has experienced rapid growth. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling down has also increased the complexity of processing and manufacturing ICs, and, for these advances to be realized, similar developments in IC manufacturing are needed.
As merely one example, interconnects, the conductive traces used to carry electrical signals between the elements that make up the circuit, are typically insulated by a dielectric material. Historically, this insulating dielectric has been silicon dioxide. However, the relative permittivity (or dielectric constant) of silicon dioxide, a measure of the insulating properties, is relatively high. Replacing silicon dioxide with a dielectric material having a lower relative permittivity can reduce interference, noise, and parasitic coupling capacitance between the interconnects. Though the benefits are promising, these low-k dielectrics have proven challenging to manufacture. Some materials are brittle, difficult to deposit, sensitive to processes such as etching, annealing, and polishing processes, unstable, and/or otherwise difficult to fabricate. For these reasons and others, although existing interconnect dielectrics have been generally adequate, they have not proved entirely satisfactory in all respects.